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Biomedical subjects

S Kereshi

Publications and source records attributed to S Kereshi.

5 recordsLinked to original sources
PubMed1984

Multiple innervation of human muscle fibers.

A combination of electrophysiological techniques, including stimulus threshold measurements, coaxial needle recordings of voluntary EMG, and evoked response analysis, has been used to show that the motor innervation of the human biceps brachii has an extensive distribution in the long axis of the muscle. Impulse collision experiments, involving either excitation at two sites or the use of stimuli of graded intensity, have demonstrated that the diffuse muscle innervation is partly a consequence of individual muscle fibers having more than one end-plate.

Adult↗
PubMed1983

Absence of fibrillation after muscle injury.

The possibility was examined that fibrillation potentials may occur in those parts of muscle fibers which become functionally denervated following segmental necrosis. Focal necrotic lesions were induced in rat semitendinosus muscles by crushing, ligating, or cutting muscle fibers. When the treated muscles were examined microscopically and recordings made with intracellular or extracellular electrodes, fibrillations were found to be either completely absent or extremely infrequent. Fibrillation potentials were also absent in the brachioradialis muscle of a human subject after myotomy. In contrast to these negative results, surgical denervation of the rat semitendinosus induced fibrillation activity within 3 days; when fully developed, fibrillations occurred in approximately one-half of the fibers at any time. The findings are considered to have significance for an understanding of the pathogenesis of those "myopathic" disorders in which fibrillations are found.

Action Potentials↗
PubMed1983

Impulse conduction velocities in human biceps brachii muscles.

Measurements of impulse conduction velocity were made in biceps brachii muscle fibers of male or female controls and of male body-builders. The technique involved exciting bundles of fibers with stimulating electrodes applied over the surface of the muscle, and recording compound action potentials with three small surface electrodes spaced 3 cm apart. By measuring latencies to the onsets and to the peaks of the negative deflections, it was possible to estimate conduction velocities in the fastest-conducting (FC) and intermediate-conducting (IC) fibers; the observed values ranged from 2.8 to 5.5 m X s-1 in normal men and women. The mean conduction velocity for FC fibers was significantly higher in body-builders than in normal men and women; the mean IC value was significantly lower in women. In all three groups of subjects a decrease in conduction velocity could be demonstrated for FC fibers at the end of 1 min of maximal isometric contraction. In the body-builders, and probably in the other two groups of subjects, the FC fibers are considered to correspond to type II muscle fibers.

Action Potentials↗
PubMed1983

A method for detecting functional weakness.

A simple electrophysiological method is described for detecting weaknes of psychiatric origin. The method involves the interpolation of a single indirect stimulus to a muscle during the course of a supposedly maximal voluntary contraction. Incomplete motor activation is revealed by the presence of a twitch superimposed on the recording of voluntary torque.

Ankle↗